[time-nuts] PCB design questions thread II

Chuck Harris cfharris at erols.com
Mon Jun 2 21:05:09 EDT 2008


Bob Paddock wrote:

>>> 2. How many layers?   In an ideal world with money no object, if I
>>> understand the current art correctly, I think I'd probably aim for a five
>>> layer
> 
> I assume that is a typo?  You can not have an odd number of layers.
> In this current 3D reality each layer has two sides.  :-)


Sure you can.  I have done 3 layer, 5 layer, and 7 layer boards.

Having done those, I will advise you not to do 3 layer, it warps.  But
everything else is easily do able.

Multilayer boards are done by bonding together combinations of
1 side, 2 side, and 0 sided laminate.  For instance:

4 layer can be made by:

2 side | 0 side | 2 side
1 side | 2 side | 1 side
1 side | 1 side | 2 side

...

5 layer can be made by:

2 side | 1 side | 1 side | 1 side
2 side | 0 side | 2 side | 1 side
2 side | 1 side | 0 side | 2 side

...

6 layer can be made by:

2 side | 0 side | 2 side | 0 side | 2 side
...

The only down side to odd numbers of layers is the supply house
has to stock 1 sided laminate.

-Chuck Harris



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